[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/smartCasts/variables/property.fir.kt

@@ -0,0 +1,11 @@
+// !WITH_NEW_INFERENCE
+class MyClass(var p: String?)
+
+fun bar(s: String): Int {
+    return s.length
+}
+
+fun foo(m: MyClass): Int {
+    m.p = "xyz"
+    return bar(m.p)
+}